Trypsin-functionalized AgAu nanoflowers for enhanced sensing of hydrogen sulfide in diverse foods: dual mechanisms of steric hindrance-mediated biothiols exclusion and silver-driven 30-fold cascade amplification

Combining the excellent optical properties, spatial structure specificity and 30-fold cascade signal amplification strategy of the trypsin-stabilized silver‑gold nanoflowers (Try-AgAuNFs), a novel nanosensing system was constructed for improving the sensing of hydrogen sulfide (H 2 S). It is worth noting that the high loading capacity of Ag can be used both for the design of the cascade signal amplification strategy, and to effectively increase the active sites of the probe, making it suitable for real-time detection of H 2 S. Excitingly, the Try on the surface of Try-AgAuNFs increases the spatial steric hindrance of the probe, effectively preventing biothiols and other amino acids from interacting with Try-AgAuNFs, thereby enabling reliable H 2 S detection and food-freshness evaluation across diverse samples. This work not only presents a novel and highly stable method for synthesising Try-AgAuNFs, but also reveals that surface-bound protein ligands can enhance probe selectivity through steric hindrance control.